1. Field of the Invention
The present invention relates to an apparatus for adjusting the torque of a D.C. motor running at constant speed.
2. Background of Related Art
The speed of a conventional dentist's hand drill motor is manually adjusted by adjusting the amount of electrical current controlled by a foot pedal regulator which varies the amount of resistance in the circuit. Under such circumstances the torque of the motor is variable and when the load on the motor increases, the speed of the motor decreases and finally stops.